Aircraft engine control



Aug. 7, 1945. F. GOSSLAU EI'AL 22,661

AIRCRAFT ENGINE CONTROL 2 sheet'-sheet 1- Original Filed April 4, 1956 jams/avian? F6??? Cossau Aug.v7, 1945. I F. Goss LAU Re. 22,661

I AIRCRAFT ENGINE CONTROL Original Filed April 4, 1936 2 Sheets-Sheet 2 w Q el .030 %6 m U5 fi m J.

' means for controlling the seamed as; 7', 1945 C um rao I S'lATE s" f PATENT, o en I eater I a auomaconraor.

" magmas, Berlin-Charlottenbnrg, and Johannes Schmidt, Berlin-Eiehhmp, Germany vested in Property Custodian .oi-mmu No. 2,137,120, dated- January 16, 1940,,

SerialNo. 72,834, Apri l 4, 1936. Application for reissue June 5, 1940,

Germany April 30, 1935 s cleans.- (c re-135.6).

Our invention relates to an arrangement and operation oi an aircrafte ine. I 1 In aircraft engines, the two factors, speed and torque, upon which the developed engine power depends, change with varying operating conditions. To what extent these two factorscontribute atany instant to develop the required power depends chiefly upon the engine and the propeller characteristics, 11 the engine characteristic and that of the propeller are not broughtinto a proper relationship with each other, it may happen that the engine'is exposed.

to danger resulting, e. g.,-from overload. orthat it operates uneconomica1ly.- in the case of an increase in speed (R. P. M.) a mechanical overload mayoccur, while overheating'mayjresult from an undue increase'in torque. Theda-tiger or an overload as the result of undue increase in speed occurs, for instance, in the case-of an engine driving a propeller particularly adapted for the take-oil,- i. e.,'a propeller having a relatively small pitch, if the engine is required to develop the maximum power when flying at high altitudes. Overheating may be caused during the take-oil if the engine is equipped with and drives a propeller particularly designed for altitude flight, i. e., a propeller having a relatively large pitch. In the first case, the engine will race due to decreased torque at high altitudes, and in the second case, it will be overloaded during take-ofl due to the great torque resulti from'the pitch of the propeller blades. l

The c iect of our invention is to provide an arrangement for controlling the operation and the'power of an aircraft engine whereby it is possible to prevent, under all operating conditions, overstraining or overheating of the enan adjustable pitch propeller and correlating at all times the speed of the engine or the pitch of the propeller with the torque or' the motive power of the engine, for example, the fuel sup- Ply. in such a manner that the torque resulting from the pitch of the propeller is always in i proper relation to the speed developed by said engine and requiredunder all flying conditions.-

Practically, this control is in the simplest case accomplished by the use of a common adiusting "device whereby the pitch of the propeller ,and

Serial No; 339,000. In

tion .to speed and torque factors that must be correlated to avoid overstraining or overheating.

The power of aircraft engines is also aflected by external conditions which vary in accordance with the altitude of night. The novel control mayreadily be adapted to take also theseconditions into account by the use of automaflcally operating governors, i. e., governors which automatically compensate for external influences and maintain at all times the desired operating f values. Common adjustingmean's may be provlded with these governors so as to enable the operator to adjust the power of the engine to the desired value, without parin special attention tooverstraining or overheating. The novel control may be carried-out byproviding a common adjusting device, e. g., a cam or the like: cooperating with sleeves of two suitable sleeve valves of hydraulic devices, one of which controls the setting of thepropeller pitch and the'other of which controls the fuel supply through the medium of a suitable throttle valve or the like.

The known manner of regulating t e operating conditions in accordance with fuel charge pressures or density of the fuel charge is insufllclent when it is desired that the control of the i proper speed and torque values or motive power gine. This object is accomplished by employing 5 is maintained at all altitudes of flight. The effect of-the varying altitudes on the engine operation, i.- e., the varying air pressures encountered, must be taken into accolmt, because they affect the residual gas proportion and thetemperature of'thefuel charges. According'to the invention, this influence is compensated for by the provision of an auxiliary governor which. corrects the Supply of the fuel in accordance with the outer iir'. This auxiliary governor is preferably made so that. it may be selectively disconnectedin order that the motor may be operated to develop. when- "trols to certain desired maximum values. .Thus,

position of .the throttle valve in the fuel 7 supply of the engine are rendered variable. The operator may thus at all times adjust the re- -quired engine power and operating conditions by means of a single handle, without paying attenever-required, the greatest possible power in accordanoe with the greatest superchargerpressure. This may be accomplished. according to the inventiornby' providing mechanism for putting the auxiliary governor out of operation upon adjustment of the manual conif the operator actuates the corresponding 'trol lever provided for the power control'oi' his engine to the-endpositlon corresponding to V the maximum output, the auxiliary governor will be automatically and motor can then be adjusted to that value of-the desired power which can be at,"

all altitudes in order to meet emergency conditions.

The control impulses for regulatingthe supply of the operating fuel in accordance with torque or motive power control independent of the alti a transmission does not revolve, by resiliently supporting it against a stationary part of the transmission casing or the like. The torque balance which is thus obtained is used for controlling the supply of the operating, fuel to the engine. The objects explained above and other objects and features not specifically noted are described more in detail-in the followingexplanations' ren+ dered with reference to the accompanying drawings. In these drawings:

Fig. 1 shows a diagrammatic representation of one embodiment of the new control system; and F18. 2 illustrates a modification with certain parts in section. v

Referring now to Fig. 1, the engine speed is controlled by a speed governor I of generally 7 known structure, which controls the adjustment of the two blades extending from the shafts 2 and I of an adjustable pitch propeller shown in According lowermost position substantially as shown in the drawings. The ports in the sleeve 6 shown ad- Jacent the places where the supply lines 9 and Ill terminate in the cylinder are blocked. With the engine at high speed, piston will be raised more or less toward its other terminal position,

depending on the engine speed at any moment, and the ports in the sleeve 5 will be correspondingly opened, either partially or wholly. However,

of the control comprising the member 28 which may be a cam or the like secured to a suitable shaft 29 and operable from a handle or hand wheel, such as 30. The sleeve 6 thus constitutes a device for setting or adjusting the propeller part diagrammatically at the left-hand side of 1 parts form an auxiliary'control by means of which the supply to and discharge of oil underpressure from the hydraulic motor 8, similar in design to a rotary valve, is governed by wayof the lines or conduits 9 and Ii. An adjusting movement of the motor I, effective to the propeller blades, is transmitted from the gear ll through the gear I! and the worm II to the propeller blades extending from the shaft 2 and through the gear I4 and worm I5 to the other propeller blade extending from the shaft 3, re-

spectively. The actuation of the gear ll of the hydraulic motor I is thus responsive to varying pressures transmitted over the pressure supply pitch to a desired mean value, which is subject to modification by the governor l in accordance with the engine speed. It may be noted that two feed lines 9 and I0 are shown on one side of the cylinder I, while three pressure lines are indicated on the other'side. reverse operation of the motor 8 must be provided for.

The throttle valve IS-"ananged m the" intake pipe I! leading to the fuel supply of the engine is actuated by a similar hydraulic control device 3! under the control of a-suitable barometric device, IS, the operation of which depends on the pressure or volume of the gas enclosed therein. The device 18 is located in a chamber Ilwhich may be connecte d to the fuel supply conduit II. If the pressure in the conduit l1 increases or decreases, the barometric member II contracts or expands correspondingly, and therefore dis-- 'mounted within the slide valve sleeve 22 disposed within the casing 23. The sleeve 22 constitutes lines land II from 'a suitable supply by way of the control comprising the cylinder 1 which contains the sleeve I and the piston i; this con- 1,-

trol being interposed in the pressure supply lines as shown in the drawings. These pressure supply lines enter into the cylinder'l, and the sleeve -l is providedwith suitable ports. Its position flow of such fluid from and to the hydraulic mo-.

The position of the sleeve I is determined 2. device for manually adjusting the throttle valve Ii and is controlled through the medium of cam 28 in a manner which is clearly'apparent from the drawings. The motor for operating the throttle 16' is thus controlled not only by the auxiliary control piston 2| but also by the sleeve 22 and consists, in the embodiment illustrated, of a generally known structure comprising a piston 25 movably arranged in a cylinder 24. The auxiliary control 31 and the control motor 25 for the throttle valve "are connected with each other by means of the conduits 26 and 21. The operation is effected by any desired control mee duim, such as, for instance, oil under pressure from a suitable supply connected to the cylinder orhousing 23 by means of thethree pipes shown in this instance for the same reason as discussed presently morein detail. 1 It will be seen, however. that the piston I constitutes an addi tional control of the flow of liquid. I This piston, which, as shown, may comprise two spaced per- 'tlons',is'movabie wit thesleevelandissuit linked to the sleeve 4 of the governor I. Any motion 'in connection with the control unit 1, namely, to

sired operating values comprising the'slide valve sleeves 6 and 22 for the governors I and II, as

- above described, are under the control of acam with the all times an indication on ascale I! of at least approximately the adjusted engine power.

The reason is that It will'be se'en irom so far rendered in the foregoing, that the invention contemplates control means for variably adjusting the pitch of the propeller blades, control means for variably adjusting the throttle .or fuel inlet for the engine, a common device for selectively pro-setting or adjusting said control means to selected desired values, together with means for additionally adjusting said flrst control means in accordance with the speed oi the engine, and means for additionally or independently adjusting said second control means-in accordancewith pressure conditions in the fuel supply 01' the engine.

The influence oi the varyin engine power due to the fluctuations oi the exhaust back pressure of the engine in response to atmospheric pressures encountered at varying altitudes of flight,

is compensated for by an auxiliary. governor comprising, in the embodiment shown in Fig. l, a

' barometric measuring device II, a hydraulic aux-' iliary control 34, and a hydraulic control motor II which corrects the position of the throttle valve I with the aid or a cam 3 which is adapted to exercise control over the pressure device II, and thus an additional corrective conpiston 4| within the sleeve 40. The flow of opcrating liquid under pressure is thus controlled for causing a corrective motion oi the piston 38. and corresponding motion of the cam 36. This cam in turn eflects the motion of cam 20 through the medium of the enclosed barometric device It.

' Accordingly, piston II of the control device 31 is moved, with the result/that the flow of operating fluid under pressure is correspondingly effected over the pipes 26, 21 to move the piston control piston 4| into its lowest position, thus causing a further opening of the throttle valve II as a consequence of operating steps previously discussed and apparent from thedrawings.

In the arrangement shown in Fig; 2, the speed is controlled in the same manner as in the arrangement. according to Fig.. 1, as may be seen from the placement of identical parts shown in the upper portion of the drawings. However, the control of the throttle valve I! is in this case not effected in accordance with the air pressure, but as a function of the torque imparted to the propeller by the engine. The propeller iswdriven by the. shaft 43 carrying the bevel gear 44 firmly mounted thereon and which rolls upon theggear 40 through the medium of bevel gears 45 and 46 carried on the shaft 41. The gear 4I-is elastically or resiliently supported against the casing 4!, as indicated at 54, so that the deflections of the gear 48 in one or the otherdirection are a- Y measure ofthe torque imparted-to the propeller or the other direction according to the angular deflection of gear 48, and operates a suitable rack or the like which is connected, asshown, at one sideto the piston of the control device 31 and at the other side to the plunger of a dash pot or oil brake 53.- This latter prevents a hunt.- ing of the control 31 and steadies its operation. The operation of the throttle I8 is controlled, as previously discussed, by a motor governed in its action by the control device 31,

We claim as our invention:

1. In combination, an engine, fuel supply means therefor, an operating shai't driven by said engine and driving an adjustable pitch propeller, hy-

draulic motor means for adjusting the pitchof 25 of the throttle motor. The valve or motor l8 is thus automatically actuated to compensate for the atmospheric pressures encountered.

The auxiliary motor or governor I5 is equipped lever 38 which upon movement of the piston a with return or resetting means comprising the brings the sleeve 40 of the control device 84 again into'the position of alignment with respect to the control piston'll. A return provision is not necessary for the governor I and the regulator it since their return is brought about by their operation as such. In the case 0! the device I, it is changed speed which brings about the alignment position between the control pis- .ton 8 and the sleeve 4; .and in the case of the device 31 (II), it is changed pressure in the conduit H which causes the proper re-alignmen-t between the control piston II and the sleeve valve 22. I I

The previously mentioned means of which the auxiliary governor compris ing the devices 38,14, and I! may be put out. of operation when it is desired to adjust the engine to the maximum output, includes-the cam denoted by numeral 42. This cam is mounted together with the cam 28 on the shalt it It the operator desires to obtain maximum "power, regardless oiatmospheric'conditions, he operates the hand wheel--30 until th e cam 42, presses the the, blades of said propeller, hydraulic motor means for adjusting said fuel supply-means, separate hydraulic pitch control and fuel control means, respectively, for controlling said motor means, common operating means for determining the setting of said hydraulic control means; and separate auxiliary means for governing the actuation of said hydraulic control 'means according to the speed oi said ensine and according to the torque of said operating shaft, respectively.

2. In an aircraft power unit having a variable pitch propeller and an internal combustion engine for driving said propeller, in combination, a device for. regulating the pitch of said propeller to control the engine speed, said device containing a hydraulic motor, adevice for regulating the charging pressure 01' said engine to'control the engine torque, said latter device containing an; other hydraulic motor, two hydraulic valves for controlling said hydraulic motors respectively,

- each of said valves comprising a manually adjust -05 mechanism. I by able portion and a self-adjusting automatic portion, a common setting mechanism under ,the

control of the pilot, said setting mechanism having-cam means operatively connected with both ,said manually adjustable portions of said valves ,-ior varying the adjustment oi saidmanually adj f justableportions in a given relation to each other.-

3. In an aircraft power unit having a. variable gins for driving said propeller, in combination, adjustable speed control means ior varying the pitch propeller and an internal combustion en- I comprising a speed govemor-and a hydraulic transmission between said governor and said propeller, adjustable throttle means for varying the charging Pressure of said engine, torque control means for actuating said throttle means so as to maintain the engine torque at a datumv value, said torque control, means comprising an actuating member and a hydraulic transmission between said member and said .throttle means, a

master control mechanism under the control of I the pilot for simultaneously varying the adjust ment of sad speed control means and said torque control means in a given relation to each other, each of said hydraulic transmissions comprising a cylinder, fluid pressure lines ending in said cylinder, a sleeve member slidably disposed in said cylinder and apiston member slidably disposed in said sleeve member, oneof said two members of each transmission being operatively connected with said master control mechanism so as to effeet a kinematically constrained movement in accordance with the movement of said master control mechanism, and said other members being connected with said propeller and said pressure-adjusting throttle means respectively.

4. The combination and structure defined in claim 1, wherein a transmission gear is interposed between said engine Operating shaft and said propeller including a supporting gear wheel which is v 22,881 pitch of said propeller, said speed control means 7. The combination with an aircraft engine and a variable pitch propeller driven by said engine, of control means for varying the pitch of said propeller responsive to the speed of said engine, cooperative regulating members, one of said members connected to an engine speed responsive unit, a device for supplying fuel to said engine, control means for adjusting said device responsive to changes in the torque applied to said propeller by said engine, cooperative regulating elements between said last-mentioned control means and said device, and manually operated settingmeans operatively connected with-said first-mentioned control means through one of .said regulating members and connected to said device through one of said regulating elements designed-for sisaid setting means, said setting means being the: only mechanical connection between the two said substantially at rest during operation of said engine and said propeller, together With'means constituting said auxiliary means for governing the actuation of said hydraulic control for adjusting the fuel supply in accordance with the torque of said operating shaft comprising, means for resiliently mounting said transmission'sup porting gear-wheel, and means operated by said gear wheel for actuating said hydraulic fuel control means in response to alterations of the torque balance of said supporting gear wheel.

5. The combination, with an aviation engine and variable pitch propeller driven thereby, of two hydraulic motors for controlling the propeller pitch'and fuel supply, respectively, two hydraulic valves for controlling said motors, respectively,

' means for manually setting said valves, means for automatically adjusting one valve in accordance with the engine speed, and means for automatically adjusting the other valve in accordance with the torque applied to said propeller.

6. The combination with an aircraft engine and of control means for varying the pitch of said propeller responsive to the speed of said engine, a device for supplying'iuel to said engine, control means for adjusting said device responsive to a variable pitch propeller driven by said engine,

changes in the torque applied to said propeller by said engine, cooperative regulating elements between said last-mentioned control means and, said device, and setting means comprising a manually operated cam operatively connected with both of said control means and connected to said device through one of said regulating-elements designed for simultaneously adjusting both of said control means in a given relation to each other;

- whereby the power output or said engine is mainmultaneously adjusting both or said control means in a given relation to each other, whereby the power output of said engineis maintained at a given value correspondingv to the adjustment of control means.

8. In an aircraft power unit having a variable pitch propeller and an internalcombustion engine for driving said propeller, in combination, an adjustable speed governor for varying the pitch of said propeller in response to variations of the speed of said engine so as to maintain said speed at a datum value, a throttle valve for varying the charging pressure of the e i e, regulating means for controlling said throttle valve so as to maintain the engine torque at a datum value, a master control device connected with both said speed governor and said regulating means for setting said datum values in a given relation to each other, and means operatively connected with said regulating means for selectively putting said regulating means out of operation upon adjustment of said master control device to a given maximum value for obtaining a maximum power output beyond the range of the automatic pressure cone trol.

9'. In an aircraft power unit having an internal combustion engine and a variable pitch propeller driven by the shaft of said engine, in combination, an adjustable-centrifugal-type governor for controlling the engine speed disposed between said engine shaft and said propeller to vary the pitch of said propeller in dependence 'upon the speed of rotation of said shaft, an automatic device for controlling the engine charge in order to maintain the torque of said engine substantially constant at an adjustable value, and a' master control device under the control of the pilot for simultaneously varying the adjustmenin'of engine speed and torque required for various conditions of flight in order to maintain a desired power output, said master device being operatively connected with said governor so as to control the setting of said governor and hence of the engine speed to be maintained by said governor, said master device being also operatively connected with said charge control device for varying the setting of said control device and thereby the en ine torque in a predetermined and constrained relation to the variation of the setting of said governor in put.

FRITZ GOSSLAU. j

'JOHANNES SCHMIDT.

accordance with said power out- 

